In his book, Slimology, Feltham reveals how you can use a low-carb, high-fat diet to accelerate weight loss and improve your cardiovascular, emotional and neurological health.

To prove his point that eating fat does not make you fat, Sam experimented with a low-carb, high-fat diet consisting of a whopping 5,794 calories a day.

Before starting his challenge, Feltham, a former bodybuilder, thought he would gain weight from consuming so many more calories than he usually did.

To his surprise, when Sam followed a LCHF diet for three weeks, he gained only 2 pounds and lost 1 inch from his waist.

Sam pictured on Day 1 and Day 21 on his high-fat, low-carb diet: He gained just 2.5 pounds and lost 1 inch off his waist despite gorging on almost 6,000 calories a day. (Photos: Sam Feltham)

In contrast, when Sam followed a low-fat, high-carb diet for three weeks, he gained 16 pounds and ballooned almost 4 inches around his waist.

Sam on Day 1, Day 10 and Day 21 of his low-fat, high-carb diet: He gained 16 pounds and 3.7 inches around his waist. (Photos: Sam Feltham)

According to Feltham, it is a high-carb diet (not dietary fat) that’s responsible for obesity and other diseases such as diabetes, heart disease, Alzheimer’s and even cancer.

“Dietary fat doesn’t really make you fat, and in fact is the least likely macro-nutrient to make you fat from overconsumption,” Feltham explained on his blog Smash The Fat. “If you ask any bodybuilder what macronutrient they manipulate in order to gain or lose weight, they’ll tell you carbohydrates.”

Feltham isn’t the only health expert to underscore the weight loss and health benefits of a low-carb, high-fat diet.

Obesity expert Dr. Eric Westman has helped thousands of people lose hundreds of thousands of pounds by following the low carb, high-fat ketogenic, Atkins and Paleo diets.